Tracheo-arterial erosion occurred in 5 cases out of 816 tracheostomized patients, i.e. an incidence of 0.6%. The complication is serious and is nearly always fatal. In one case, treatment was successful, but the other four patients died as a result of massive haemorrhage. On the basis of these cases the factors leading to this complication and the possibilities of treatment are discussed. In one case the main cause of innominate artery erosion was the low lying tracheostomy. This patient was rapidly resuscitated, the blood volume was restored, bleeding controlled by direct finger pressure on the innominate artery and an emergency operation was performed immediately. The innominate artery was excluded from circulation and bypassed with an autogenous venous graft. The patient recovered and is doing well after a follow-up of two and half years.